Prevalence of health risk behaviours related to non-communicable diseases amongst South African university students: a systematic review.

BACKGROUND: Engagement in risk behaviours adopted during university continues after graduation, increasing the risk of non-communicable diseases (NCDs). This systematic review aimed to investigate the prevalence of NCD risk behaviours amongst South African university students. METHODS: PubMed and Scopus databases were searched (January 1990-April 2022) for studies investigating alcohol consumption, cigarette smoking, inadequate consumption of fruits and vegetables and physical inactivity. Study qualities were assessed with the Joanna Briggs Institute critical appraisal and levels of evidence checklists. An overall prevalence percentage was obtained for each risk behaviour. RESULTS: A total of 50 studies (n = 26 624 students) were included. A range of 44.8-75.0% of students consumed inadequate servings of fruits and vegetables. Just over 54% consumed alcohol (95% confidence intervals [95%CI]:54.0-55.5%). A significantly higher percentage of males (44.2%) than females (25.8%) drank heavily (P < 0.001). Approximately one-third (34.8%, 95%CI:33.4-36.3%) were sedentary and 39.0% (95%CI:37.5-40.4%) were insufficiently active. Almost one-fifth (17.9%, 95%CI:17.3-18.5%) smoked cigarettes, being significantly more prevalent amongst males (21.8%) than females (13.5%) (P < 0.001). A total of 10% smoked 1-10 cigarettes/day and 1.2% smoked >10 cigarettes/day. CONCLUSION: High percentages of South African students eat inadequate servings of fruits and vegetables, consume alcohol are physically inactive and smoke cigarettes. South African universities should implement screening measures and health campaigns.

Risk factors associated with acute respiratory illnesses in athletes: a systematic review by a subgroup of the IOC consensus on 'acute respiratory illness in the athlete'.

OBJECTIVE: To review risk factors associated with acute respiratory illness (ARill) in athletes, including non-infectious ARill and suspected or confirmed acute respiratory infections (ARinf). DESIGN: Systematic review. DATA SOURCES: Electronic databases: PubMed-Medline, EbscoHost and Web of Science. ELIGIBILITY CRITERIA: Original research articles published between January 1990 and July 2020 in English were searched for prospective and retrospective full text studies that reported quantitative data on risk factors associated with ARill/ARinf in athletes, at any level of performance (elite/non-elite), aged 15-65 years. RESULTS: 48 studies (n=19 390 athletes) were included in the study. Risk factors associated with ARill/ARinf were: increased training monotony, endurance training programmes, lack of tapering, training during winter or at altitude, international travel and vitamin D deficits. Low tear-(SIgA) and salivary-(IgA) were immune biomarkers associated with ARill/ARinf. CONCLUSIONS: Modifiable training and environmental risk factors could be considered by sports coaches and athletes to reduce the risk of ARill/ARinf. Clinicians working with athletes can consider assessing and treating specific nutritional deficiencies such as vitamin D. More research regarding the role and clinical application of measuring immune biomarkers in athletes at high risk of ARill/ARinf is warranted. PROSPERO REGISTRATION NUMBER: CRD42020160928.

Association between thermal responses, medical events, performance, heat acclimation and health status in male and female elite athletes during the 2019 Doha World Athletics Championships.

PURPOSE: To determine associations between thermal responses, medical events, performance, heat acclimation and health status during a World Athletics Championships in hot-humid conditions. METHODS: From 305 marathon and race-walk starters, 83 completed a preparticipation questionnaire on health and acclimation. Core (Tcore; ingestible pill) and skin (Tskin; thermal camera) temperatures were measured in-competition in 56 and 107 athletes, respectively. 70 in-race medical events were analysed retrospectively. Performance (% personal best) and did not finish (DNF) were extracted from official results. RESULTS: Peak Tcore during competition reached 39.6°C±0.6°C (maximum 41.1°C). Tskin decreased from 32.2°C±1.3°C to 31.0°C±1.4°C during the races (p<0.001). Tcore was not related to DNF (25% of starters) or medical events (p≥0.150), whereas Tskin, Tskin rate of decrease and Tcore-to-Tskin gradient were (p≤0.029). A third of the athletes reported symptoms in the 10 days preceding the event, mainly insomnia, diarrhoea and stomach pain, with diarrhoea (9% of athletes) increasing the risk of in-race medical events (71% vs 17%, p<0.001). Athletes (63%) who performed 5-30 days heat acclimation before the competition: ranked better (18±13 vs 28±13, p=0.009), displayed a lower peak Tcore (39.4°C±0.4°C vs 39.8°C±0.7°C, p=0.044) and larger in-race decrease in Tskin (-1.4°C±1.0°C vs -0.9°C±1.2°C, p=0.060), than non-acclimated athletes. Although not significant, they also showed lower DNF (19% vs 30%, p=0.273) and medical events (19% vs 32%, p=0.179). CONCLUSION: Tskin, Tskin rate of decrease and Tcore-to-Tskin gradient were important indicators of heat tolerance. While heat-acclimated athletes ranked better, recent diarrhoea represented a significant risk factor for DNF and in-race medical events.

Hydration and cooling in elite athletes: relationship with performance, body mass loss and body temperatures during the Doha 2019 IAAF World Athletics Championships.

PURPOSE: To characterise hydration, cooling, body mass loss, and core (Tcore) and skin (Tsk) temperatures during World Athletics Championships in hot-humid conditions. METHODS: Marathon and race-walk (20 km and 50 km) athletes (n=83, 36 women) completed a pre-race questionnaire. Pre-race and post-race body weight (n=74), Tcore (n=56) and Tsk (n=49; thermography) were measured. RESULTS: Most athletes (93%) had a pre-planned drinking strategy (electrolytes (83%), carbohydrates (81%)) while ice slurry was less common (11%; p<0.001). More men than women relied on electrolytes and carbohydrates (91%-93% vs 67%-72%, p≤0.029). Drinking strategies were based on personal experience (91%) rather than external sources (p<0.001). Most athletes (80%) planned pre-cooling (ice vests (53%), cold towels (45%), neck collars (21%) and ice slurry (21%)) and/or mid-cooling (93%; head/face dousing (65%) and cold water ingestion (52%)). Menthol usage was negligible (1%-2%). Pre-race Tcore was lower in athletes using ice vests (37.5°C±0.4°C vs 37.8°C±0.3°C, p=0.024). Tcore (pre-race 37.7°C±0.3°C, post-race 39.6°C±0.6°C) was independent of event, ranking or performance (p≥0.225). Pre-race Tsk was correlated with faster race completion (r=0.32, p=0.046) and was higher in non-finishers (did not finish (DNF); 33.8°C±0.9°C vs 32.6°C±1.4°C, p=0.017). Body mass loss was higher in men than women (-2.8±1.5% vs -1.3±1.6%, p<0.001), although not associated with performance. CONCLUSION: Most athletes' hydration strategies were pre-planned based on personal experience. Ice vests were the most adopted pre-cooling strategy and the only one minimising Tcore, suggesting that event organisers should be cognisant of logistics (ie, freezers). Dehydration was moderate and unrelated to performance. Pre-race Tsk was related to performance and DNF, suggesting that Tsk modulation should be incorporated into pre-race strategies.

Race walking gait and its influence on race walking economy in world-class race walkers.

AIM: The aim of this study was to determine the relationships between biomechanical parameters of the gait cycle and race walking economy in world-class Olympic race walkers. METHODS: Twenty-One world-class race walkers possessing the Olympic qualifying standard participated in this study. Participants completed an incremental race walking test starting at 10 km·h-1, where race walking economy (ml·kg-1·km-1) and spatiotemporal gait variables were analysed at different speeds. RESULTS: 20-km race walking performance was related to race walking economy, being the fastest race walkers those displaying reduced oxygen cost at a given speed (R = 0.760, p < 0.001). Longer ground contact times, shorter flight times, longer midstance sub-phase and shorter propulsive sub-phase during stance were related to a better race walking economy (moderate effect, p < 0.05). CONCLUSION: According to the results of this study, the fastest race walkers were more economi cal than the lesser performers. Similarly, shorter flight times are associated with a more efficient race walking economy. Coaches and race walkers should avoid modifying their race walking style by increasing flight times, as it may not only impair economy, but also lead to disqualification.

Associations between psychological distress and facets of mindfulness: Implications for campus-based university wellness services.

OBJECTIVES: To investigate associations between components of psychological distress and five facets of mindfulness (i.e. observing; describing; acting with awareness; non-reactivity; non-judging). PARTICIPANTS: Students from a university in South Africa (n = 174). METHODS: This cross-sectional study assessed psychological distress and mindfulness using the K10 and Five Facet Mindfulness Questionnaire. Multivariate regression analysis identified associations between psychological distress and facets of mindfulness, controlling for demographics. RESULTS: Prevalence of psychological distress was 56.9% (95% CI 49.2%-64.4%). Acting with awareness, non-reactivity, and non-judging predicted significantly lower psychological distress, whereas observing and describing did not. Acting with awareness was the only facet of mindfulness that consistently predicted lower levels of negative affect, fatigue, nervousness, and agitation. CONCLUSIONS: Acting with awareness appears to be a key component of psychological wellbeing. To advance theory and practice, future research should consider why and how various facets of mindfulness predict lower psychological distress and its components among university students.

Thermoregulatory responses during road races in hot-humid conditions at the 2019 Athletics World Championships.

The purpose of this study was to characterize thermoregulatory and performance responses of elite road-race athletes, while competing in hot, humid, night-time conditions during the 2019 IAAF World Athletic Championships. Male and female athletes, competing in the 20 km racewalk (n = 20 males, 24 females), 50 km racewalk (n = 19 males, 8 females), and marathon (n = 15 males, 22 females) participated. Exposed mean skin (Tsk) and continuous core body (Tc) temperature were recorded with infrared thermography and ingestible telemetry pill, respectively. The range of ambient conditions (recorded roadside) was 29.3°C-32.7°C air temperature, 46%-81% relative humidity, 0.1-1.7 m·s-1 air velocity, and 23.5°C-30.6°C wet bulb globe temperature. Tc increased by 1.5 ± 0.1°C but mean Tsk decreased by 1.5 ± 0.4°C over the duration of the races. Tsk and Tc changed most rapidly at the start of the races and then plateaued, with Tc showing a rapid increase again at the end, in a pattern mirroring pacing. Performance times were between 3% and 20% (mean = 113 ± 6%) longer during the championships compared with the personal best (PB) of athletes. Overall mean performance relative to PB was correlated with the wet-bulb globe temperature (WBGT) of each race (R2 = 0.89), but not with thermophysiological variables (R2 ≤ 0.3). As previously reported in exercise heat stress, in this field study Tc rose with exercise duration, whereas Tsk showed a decline. The latter contradicts the commonly recorded rise and plateau in laboratory studies at similar ambient temperatures but without realistic air movement.NEW & NOTEWORTHY This paper provides a kinetic observation of both core and skin temperatures in 108 elite athletes, during various outdoor competition events, adding to the very limited data so far available in the literature taken during elite competitions. The field skin temperature findings contrast previous laboratory findings, likely due to differences in relative air velocity and its impact on the evaporation of sweat. The rapid rise in skin temperature following cessation of exercise highlights the importance of infrared thermography measurements being taken during motion, not during breaks, when being used as a measurement of skin temperature during exercise.

Training Characteristics of a World Championship 5000-m Finalist and Multiple Continental Record Holder Over the Year Leading to a World Championship Final.

PURPOSE: Optimal training for endurance performance remains a debated topic. In this case study, the training of a world-class middle-/long-distance runner over a year's duration is presented. METHODS: The training is analyzed via 2 methods to define training intensity distribution (TID) (1) by physiological zones and (2) by zones based on race pace. TID was analyzed over the full season, but also over the final 6, 12, and 26 weeks to allow for consideration of periodization/phases of season. The results of both methods are compared. Other training data measured include volume and number of sessions. RESULTS: The average weekly volume for the athlete was 145.8 (24.8) km·wk-1. TID by physiological analysis was polarized for the last 6 weeks of the season but was pyramidal when analyzed over the final 12, 26, and 52 weeks of the season. TID by race-pace analysis was pyramidal across all time points. The athlete finished 12th in the final of the World Championship 5000-m and made the semifinal of the 1500-m. He was ranked in the top 16 in the world for 1500, 5000, and 10,000 m. CONCLUSION: The results of this study demonstrate a potential flaw with recent work suggesting polarized training as the most effective means to improve endurance performance. Here, different analysis methods produced 2 different types of TID. A polarized distribution was only seen when analyzed by physiological approach, and only during the last 6 weeks of a 52-week season. Longer-term prospective studies relating performance and physiological changes are suggested.

Energetics in elite race walkers.

Race walkers must conform to a unique gait pattern with no visible loss of contact with the ground. However, how the gait pattern affects the race walking economy is unclear. We investigated the energy cost (amount of energy spent per distance unit) at different race walking velocities and over a 25 km hybrid walk. Twenty-one international-level male race walkers (V˙O2peak 63.8 ± 4.3 ml kg-1 min-1, age 31 ± 5 y, body mass 68.1 ± 7.0 kg) performed an incremental treadmill test consisting of 4 × 4 min submaximal stages with 1 km h-1 increments, and a 25 km submaximal hybrid walk (treadmill-overground) on separate days. Energy cost was measured continuously during the submaximal test and at km 0-1, 6-7, 12-13, 18-19, 23-24 of the 25 km hybrid walk. The CRW was similar across the four submaximal stages where half the athletes completed them at a higher (1 km h-1) absolute velocity (-0.01-0.15 ± ∼0.65); range of standardised differences ±90% CL, with a tendency for higher performing athletes to have a lower CRW when this was analysed during absolute race walking velocities of 12, 13 and 14 km-1 for the entire cohort (0.46-0.49 ± ∼0.67). There was no substantial change in CRW from the start to the end of the 25 km walk for the entire cohort (0.08 ± 2.2; standardised change ±90% CL). Elite race walkers are characterised by having a similar energy cost among athletes who perform at the same relative exercise intensity, and substantially higher energetics than counterpart elite endurance runners.

Training intensity distribution analysis by race pace vs. physiological approach in world-class middle- and long-distance runners.

This study aimed to analyse the training intensity distribution (TID) of a group of 7 world-class middle- and long-distance runners over 50 weeks using two different approaches to organise TID zones: (1) based on individual specific race pace and; (2) based on physiological parameters. Analysed training data included training volume, intensity and frequency. The average weekly volume for the group was 135.4 ± 29.4 km·week-1. Training volumes for Z1, Z2 and Z3 were 88.5 ± 1.1%, 7.4 ± 0.8% and 4.1 ± 0.7% respectively for race-pace based approach, and 87.2 ± 1.2%, 6.1 ± 0.7% and 6.6 ± 0.9% respectively for the physiological approach. Differences were found between the approaches in Z2 (large effect, ES = 1.20) and Z3 (moderate effect, ES = 0.93). The approach based on race-pace zones produced pyramidal distributions in both middle- and long-distance runners across all phases of the season. The physiological approach produced polarised and pyramidal distributions depending of the phase of the season in the middle-distance runners, and pyramidal type TID across all phases of the season in the long-distance runners. The results of this study demonstrate that the training analysis in a world-class group of runners shows different TID when assessed relative to race pace versus to physiological zones. This highlights a potential deficiency in training analysis and prescription methods which do not make reference to specific performance. An approach which makes reference to both physiological and performance measures may allow for a more consistent and logical analysis.

Physiological Indicators of Trail Running Performance: A Systematic Review.

PURPOSE: To provide a systematic overview of physiological parameters used to determine the training status of a trail runner and how well these parameters correlate with real-world trail running performance. METHOD: An electronic literature search of the PubMed and Scopus digital databases was performed. Combinations of the terms "trail run" or "trail runner" or "trail running" and "performance" were used as search terms. Seven studies met the inclusion criteria. RESULTS: Trail running performance most commonly correlated (mean [SD]) with maximal aerobic capacity (71%; r = -.50 [.32]), lactate threshold (57%; r = -.48 [.28]), velocity at maximal aerobic capacity (43%; r = -.68 [.08]), running economy (43%; r = -.31 [.22]), body fat percentage (43%; r = .55 [.21]), and age (43%; r = .52 [.14]). Regression analyses in 2 studies were based on a single variable predicting 48% to 60% of performance variation, whereas 5 studies included multiple variable regression analyses predicting 48% to 99% of performance variation. CONCLUSIONS: Trail running performance is multifaceted. The classic endurance model shows a weaker association with performance in trail running than in road running. Certain variables associated with trail running research (such as testing procedures, race profiles, and study participants) hinder the execution of comparative studies. Future research should employ trail-specific testing protocols and clear, objective descriptions of both the race profile and participants' training status.

Anthropometric characteristics of top-class Olympic race walkers.

BACKGROUND: Typical training programmes in elite race walkers involve high training volumes at low and moderate intensities, which have been reported to induce functional and structural adaptations at an anthropometric level. Since anthropometrical variables are closely related to movement efficiency and performance in endurance events, the aim of this study was to describe the anthropometric profile of world-class race walkers. METHODS: Twenty-nine world-class race walkers (21 men and 8 women) participated in this study. Anthropometric characteristics, including height, body mass, eight skinfolds, five girths and four bone breadths were measured. Body composition, somatotype, somatotype dispersion mean, somatotype attitudinal mean and height to weight ratio, as well as skinfolds extremity to trunk ratio were also calculated. RESULTS: Mean height, body mass and body mass index were 177.1±7.1 cm, 66.4±5.8 kg, and 21.2±1.3 kg·m2 for men and 165.6±4.5 cm, 53.6±3.7 kg, and 19.6±1.6 kg· m2 for women, respectively. Women presented greater body fat content (6.7±0.6 vs. 12.2±0.8%; very large effect), less muscle mass (65.6±4.6 vs. 61.6±2.6 kg; large effect), and were more endomorphic (large effect) than men. Men specialists in 20-km showed greater muscle mass (66.7±4.9 vs. 64.4±4.3 kg; moderate effect), and slightly higher skinfolds, girths, body fat content and were more mesomorphic than 50-km specialists (moderate effect). CONCLUSIONS: The present study expands the limited knowledge on the anthropometric characteristics and somatotype elements of elite top-class race walkers. The characterisation of the morphology of elite race walkers provides coaches a reference values to control the training development of the race walker, as well as providing reference values to improve talent identification.

Muscle Activation Patterns Correlate With Race Walking Economy in Elite Race Walkers: A Waveform Analysis.

PURPOSE: To analyze the association between muscle activation patterns on oxygen cost of transport in elite race walkers over the entire gait waveform. METHODS: A total of 21 Olympic race walkers performed overground walking trials at 14 km·h-1 where muscle activity of the gluteus maximus, adductor magnus, rectus femoris, biceps femoris, medial gastrocnemius, and tibialis anterior were recorded. Race walking economy was determined by performing an incremental treadmill test ending at 14 km·h-1. RESULTS: This study found that more-economical race walkers exhibit greater gluteus maximus (P = .022, r = .716), biceps femoris (P = .011, r = .801), and medial gastrocnemius (P = .041, r = .662) activation prior to initial contact and weight acceptance. In addition, during the propulsive and the early swing phase, race walkers with higher activation of the rectus femoris (P = .021, r = .798) exhibited better race walking economy. CONCLUSIONS: This study suggests that the neuromuscular system is optimally coordinated through varying muscle activation to reduce the metabolic demand of race walking. These findings highlight the importance of proximal posterior muscle activation during initial contact and hip-flexor activation during early swing phase, which are associated with efficient energy transfer. Practically, race walking coaches may find this information useful in the development of specific training strategies on technique.

Different competition approaches in a world-class 50-km racewalker during an Olympic year.

The aim of this case study was to compare the competition approaches for the Race Walking World Cup and the Olympic Games of a world-class 50-km racewalker. Total training volumes, intensity distribution, performance tests, high altitude stages and the evolution of his haematological values during the season were analysed. The last 12 weeks before the Race Walking World Cup (Approach 1) and the Olympic Games (Approach 2) were used for data analysis. Approach 1 was characterized by lower training volumes (791.7±192.8 min vs. 959.0±120.0 min ES=1.0, large effect) and a higher incidence of high intensity training (ES<0.8, large effect), than Approach 2. Approach 1 resulted in lower blood lactate values at set speeds, better haematological values and a better performance in the Race Walking World Cup than in the Olympic Games (3h47'30'' vs. 3h51'30"). According to the results of this analysis, it seems that a training strategy characterised by a higher incidence of high intensity training and lower volume of work may lead to superior training adaptations and performance in 50-km racewalking. This may help elite racewalkers and their coaches to achieve an optimum performance in their major goal competitions.